Texas Railroad Commision

What is the Eagle Ford Shale?

The Eagle Ford Shale is a hydrocarbon producing formation of significant importance due to its capability of producing both gas and more oil than other traditional shale plays.  It contains a much higher carbonate shale percentage, upwards to 70% in south Texas, and becomes shallower and the shale content increases as it moves to the northwest.  The high percentage of carbonate makes it more brittle and “fracable”.  The shale play trends across Texas from the Mexican border up into East Texas, roughly 50 miles wide and 400 miles long with an average thickness of 250 feet.  It is Cretaceous in age resting between the Austin Chalk and the Buda Lime at a depth of approximately 4,000 to 12,000 feet.  It is the source rock for the Austin Chalk and the giant East Texas Field.  The name has often been misspelled as “Eagleford”.  A great picture can be found at the Energy Information Administration (EIA) http://www.eia.gov/oil_gas/rpd/shaleusa9.pdf which shows the structural contours and windows for the oil, wet gas/condensate and dry gas.

Texas Railroad Commission Website:


Texas Railroad Commission map of Eagle Ford